Comparative analysis of synthetic and conventional magnetic resonance imaging features across various brain regions

Purpose: This study compared the contrast characteristics of synthetic magnetic resonance imaging (MRI) with conventional MRI in normal brain tissue and tumor-related areas. Methods: A retrospective analysis was performed on 60 patients who underwent noncontrast synthetic and conventional MRIs. Synthetic MRI was reconstructed to match conventional MRI parameters using magnetization-prepared 2 rapid acquisition gradient echoes and multiple spin echo sequences. The contrast in T1-weighted (T1WI), fluid-attenuated inversion recovery (FLAIR), and T2-weighted images (T2WI) was assessed across various brain regions and tumor-related areas. Relaxation times and dynamic range were analyzed, and a five-point visual assessment was conducted for overall image quality. Results: Synthetic MRI demonstrated significantly higher contrast in T1WI across all normal brain regions and most tumor-related areas (P < 0.01). For FLAIR, synthetic MRI exhibited superior contrast around the putamen (P < 0.05) but variable results in other regions. In T2WI, synthetic MRI showed higher contrast overall (P < 0.01), though conventional MRI performed better in some comparisons. Relaxation times of synthetic MRI were generally consistent with literature values but differed in cerebrospinal fluid (CSF) and lesion areas. The dynamic range of synthetic MRI was narrower. Visual assessments showed that synthetic MRI outperformed conventional MRI in all sequences except FLAIR (P < 0.01). Conclusion: Synthetic MRI provided superior overall image quality for T1WI and T2WI, particularly achieving higher T1WI contrast. However, synthetic FLAIR had inferior overall quality despite better contrast around the putamen. Caution is needed in T2WI for CSF and edema depiction, which have relatively long T2 relaxation times.